JPH07188389A - Epoxy resin composition and semi-conductor sealing device - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition containing a specified epoxy resin, a dicyclopentadiene-phenol polymer, a methyl methacrylate-butadiene- styrene copolymer resin and fine alumina powder, useful for sealing of a semi- conductor and excellent in moisture resistance, moldability, etc. CONSTITUTION:This resin composition is composed mainly of (A) an epoxy resin of formula I[R<1> is CmH2m+1; (m) is an integer of >=0; (n) is an integer of >=1], (B) a dicyclopentadiene-phenol polymer of formula II [R<2> is ClH2l+1; (l) and (n) are each an integer of >=0], (C) a methyl methacrylate-butadiene- styrene copolymer resin and (D) 25 to 90wt.% fine alumina powder (average particle size is 10 to 50um) and excellent in solder reflow heat resistance also. This epoxy resin composition is excellent in thin-wall part filling properties and mold abrasion resistance and having a low thermal expansion coefficient, an excellent thermal conductivity and an excellent heat dissipation property. These properties are well-balanced and the reliability is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition and a semiconductor encapsulation device which are excellent in moisture resistance, moldability and solder heat resistance and have a good balance of properties.

[0002]

2. Description of the Related Art Conventionally, a method of sealing electronic parts such as diodes, transistors and integrated circuits with a thermosetting resin has been used. This sealing resin is economically advantageous as compared with the hermetic sealing method using glass, metal, or ceramic, and is therefore widely put into practical use. Among thermosetting resins, epoxy resins are most commonly used as the encapsulating resin in terms of reliability and price. Hardeners such as acid anhydrides, aromatic amines, and novolac-type phenolic resins are used as epoxy resins. Among these, epoxy resins using novolac-type phenolic resins as hardeners use other hardeners. Compared to other products, it has excellent moldability and reliability, is non-toxic, and is inexpensive,
Widely used as a resin for semiconductor encapsulation. As the filler, fused silica powder or crystalline silica powder is generally used together with the above-mentioned curing agent. In recent years, along with surface mounting of semiconductor components and further increase in power consumption, development of a semiconductor encapsulating resin having good heat dissipation, solder heat resistance, and low stress has been demanded.

However, a resin composition comprising an epoxy resin having a novolac type phenolic resin as a curing agent and a fused silica powder has a small coefficient of thermal expansion, good moisture resistance, and a bonding wire open by a hot and cold cycle test. Although it has a feature that it is excellent in resin cracks, pellet cracks, etc., it has a drawback that its function cannot be fulfilled in a power semiconductor with large heat consumption because of its poor heat dissipation due to its low thermal conductivity. On the other hand, in a resin composition comprising an epoxy resin using a novolac type phenol resin as a curing agent and crystalline silica powder, increasing the compounding ratio of the crystalline silica powder increases the thermal conductivity and also improves heat dissipation. However, the coefficient of thermal expansion is large,
There is a drawback in that the reliability with respect to moisture resistance also deteriorates. Further, the sealed product obtained from this resin composition has the drawbacks that the mechanical properties are deteriorated and that the die is largely worn during molding. Therefore, there is a limit in achieving high thermal conductivity of the encapsulating resin composition using silica powder.

[0004]

The present invention has been made to solve the above-mentioned drawbacks, and is excellent in moisture resistance, solder heat resistance, moldability, especially filling property of thin portion, and die abrasion resistance. , Small coefficient of thermal expansion, good thermal conductivity and heat dissipation,
It is an object of the present invention to provide a highly reliable epoxy resin and a semiconductor encapsulation device having well-balanced characteristics thereof.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that by using a specific epoxy resin, a specific phenolic polymer, and a specific alumina powder, The inventors have found that the above objects can be achieved and completed the present invention.

That is, the present invention provides (A) an epoxy resin represented by the following general formula:

[0007]

[Chemical 3] (However, in the formula, R ¹ represents C _m H _{2m + 1} , m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more.) (B) Dicyclohexyl represented by the following general formula Pentadiene / phenolic polymer

[0008]

[Chemical 4] (However, in the formula, R ² is _Cl H _{2l + 1} , and l and n are 0 or 1
Each of the above integers is represented.) (C) Methyl methacrylate / butadiene / styrene copolymer resin and (D) Alumina powder having an average particle size of 10 to 50 μm are essential components, and the alumina powder of (D) is a resin composition. The epoxy resin composition is characterized by being contained in a proportion of 25 to 90% by weight. A semiconductor encapsulation device is obtained by encapsulating a semiconductor chip with a cured product of this epoxy resin composition.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, those represented by the following general formula are used.

[0011]

[Chemical 5] (Wherein R ¹ represents C _m H _{2m + 1} , m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more, respectively) (B) Dicyclopentadiene / phenol used in the present invention The polymer has a skeleton structure represented by the above general formula 4 and is widely included without being particularly limited in molecular structure, molecular weight and the like. Further, a novolac type phenol resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof can be used in combination.

The (C) methylmethacrylate / butadiene / styrene copolymer resin used in the present invention is a copolymer of methylmethacrylate, butadiene and styrene, and is not limited to the composition ratio of each monomer. The mixing ratio of this methyl methacrylate / butadiene / styrene copolymer resin is 0.
It is preferable to add 1 to 10% by weight.
More preferably, it is within the range of 1.0 to 5.0% by weight. If the proportion is less than 0.1% by weight, the elastic modulus is not effective, and if it exceeds 10% by weight, the moldability is poor and it is not suitable for practical use.

The (D) alumina powder used in the present invention is obtained by removing coarse particles on a 150-mesh sieve and has an average particle diameter of 10 to 50 μm. Average particle size is 10 μm
When it is less than 50 μm or more than 50 μm, there is a problem in fluidity and workability, which is not preferable. In particular, if the particle size is coarse on a 150-mesh screen, wire gate clogging, wire flow, die wear, etc. may occur during molding, which is not preferable. On the other hand, if the diameter is too small, the specific surface area increases and the filling property deteriorates, which is not preferable. Alumina powder is a rhombohedral αAl
₂ O ₃ . The alumina powder is preferably contained in a proportion of 25 to 90% by weight based on the total resin composition. If the proportion is less than 25% by weight, the coefficient of thermal expansion increases and the thermal conductivity decreases, which is not preferable.
Further, if it exceeds 90% by weight, the dryness becomes large and the moldability is poor and it is not suitable for practical use.

The epoxy resin composition of the present invention contains a specific epoxy resin, a specific dicyclopentadiene / phenol polymer, a methyl methacrylate / butadiene / styrene copolymer resin and a specific alumina powder as essential components. As long as it does not violate the purpose of the invention, and if necessary, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins and other mold release agents, chlorinated paraffins, bromine, etc. A flame retardant such as toluene, hexabromobenzene and antimony trioxide, a coloring agent such as carbon black and red iron oxide, various curing agents and the like can be appropriately added and blended.

The general method for preparing the epoxy resin composition of the present invention as a molding material is to use the above-mentioned specific epoxy resin, specific dicyclopentadiene / phenol polymer, methyl methacrylate / butadiene / styrene copolymer resin, A specific alumina powder and other raw material components selected to have a predetermined composition ratio are sufficiently mixed with a mixer, etc., and then subjected to melt mixing treatment with a hot roll, followed by cooling and solidifying and crushing into an appropriate size for molding. It can be a material. The molding material thus obtained is
When applied to sealing, coating, insulation, etc. of electronic parts such as semiconductor devices or electric parts, excellent characteristics and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the above-mentioned molding material. The semiconductor chip to be sealed is not particularly limited to, for example, an integrated circuit, a large scale integrated circuit, a transistor, a thyristor, a diode and the like. The most common method of sealing is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The epoxy resin composition is heated and cured at the time of encapsulation, and finally a semiconductor encapsulating device encapsulated by the cured product of the composition is obtained. For curing by heating, it is desirable to heat and cure at 150 ° C or higher.

[0017]

The present invention uses a specific epoxy resin, a specific dicyclopentadiene / phenol polymer, a methylmethacrylate / butadiene / styrene copolymer resin, and a specific alumina powder in an epoxy resin composition to obtain moisture resistance. , A resin composition excellent in moldability and mold abrasion resistance, having a small coefficient of thermal expansion, good thermal conductivity, and good heat dissipation, and a highly reliable resin composition with well-balanced characteristics thereof. By using the composition, a highly reliable semiconductor device can be manufactured.

[0018]

EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, “%” means “% by weight”.

Example 1 16% of the epoxy resin shown in Chemical Formula 5 above, 8% of the dicyclopentadiene-phenol polymer shown in Chemical Formula 4 above, alumina powder (average after removing coarse particles on a 150 mesh sieve) 71% of particle size 17 μm), 2% of methylmethacrylate / butadiene / styrene copolymer resin and 3% of mold release agent, etc. were mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material. .

Example 2 In Example 1, instead of 71% of alumina powder (average particle size of 17 μm obtained by removing coarse particles on a 150-mesh screen), alumina powder (coarse particles on a 150-mesh screen was removed). 31% with an average particle size of 17 μm and crystalline silica powder (average particle size of 38 μm)
) A molding material was manufactured in the same manner as in Example 1 except that a mixed powder with 40% was used.

Comparative Example 1 Cresol novolac epoxy resin (epoxy equivalent 215
) 18%, novolac type phenolic resin (phenol equivalent 107) 9%, alumina powder (average particle size 17 μm after removal of coarse particles on 150 mesh sieve) 71%, methyl methacrylate / butadiene / styrene copolymer resin 2% and A molding material was manufactured in the same manner as in Example 1 by mixing 3% of a release agent and the like at room temperature.

Comparative Example 2 71% of alumina powder (average particle size of 60 μm after passing through 60 mesh) was replaced with 71% of alumina powder (average particle size of 17 μm after removing coarse particles on a 150-mesh sieve) in Comparative Example 1.
A molding material was manufactured in the same manner as in Comparative Example 1 except that was used.

Semiconductor chips were encapsulated using the molding materials produced in Examples 1 and 2 and Comparative Examples 1 and 2, and cured by heating at 170 ° C. to produce semiconductor encapsulation devices. Various tests were performed on the molding material and the semiconductor encapsulation device, and the results are shown in Table 1. The epoxy resin composition and the semiconductor encapsulation device of the present invention have good thermal characteristics, moisture resistance, and solder heat resistance. It was excellent in moldability and moldability, and the remarkable effect of the present invention could be confirmed.

[0024]

[Table 1] * 1: Diameter 50 mm, thickness 3 mm by transfer molding
A molded article of the above was prepared, and the molded article was allowed to stand in saturated steam at 127 ° C. and 2.5 atm for 24 hours and measured by the increased weight. * 2: Make a molded product similar to the case of water absorption, 175 ℃, 8
After post-curing for a certain time, a test piece of an appropriate size was prepared and measured using a thermomechanical analyzer. * 3: Tested according to JIS-K-6911. * 4: The semiconductor sealing device was measured at room temperature using a rapid thermal conductivity meter (Showa Denko KK, trade name QTM-MD). * 5: Using a 120-cavity 16-pin P mold, the molding material was transfer-molded at 170 ° C. for 3 minutes, and the filling property was evaluated. ○ mark: good, × mark: bad * 6: Using a molding material, attach a silicon chip with two or more aluminum wires to a normal 42 alloy frame and transfer mold at 175 ° C for 2 minutes.
Post-curing was performed at 175 ° C for 8 hours. The molded product thus obtained is subjected to moisture absorption treatment at 40 ° C., 95% RH for 100 hours in advance, and then
It was immersed in a solder bath at 250 ° C for 10 seconds. After that, 127 ℃,
PCT was performed in saturated steam of 2.5 atm and 50% disconnection due to corrosion of aluminum was evaluated as defective. * 7: 8 × 8mm dummy chip with Q-FP (14 × 14 × 1.4
mm) package, transfer molding was performed using the molding material at 175 ° C for 2 minutes, and then post-curing was performed at 175 ° C for 8 hours. The semiconductor encapsulation device obtained in this way is 85 ℃, 85%,
After absorbing moisture for 24 hours, it was immersed in a solder bath at 240 ° C for 1 minute. After that, observe the package surface with a stereomicroscope,
The occurrence of external resin cracks was evaluated. * 8: The molding material is preheated, and transfer molding is performed at 175 ° C using a die with a 0.5 mm diameter hard chrome plating material flow hole. It was evaluated by the number of shots when the hole diameter was 5% worn.

[0025]

As is apparent from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulating device of the present invention have the moisture resistance, the solder heat resistance, the moldability of the resin composition, especially the filling property of the thin portion. Excellent in mold abrasion resistance, small coefficient of thermal expansion, good thermal conductivity and heat dissipation, and well-balanced characteristics of them, and a highly reliable semiconductor encapsulation device can be manufactured. .

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Claims (2)

[Claims] 1. An epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ represents C _m H _{2m + 1} , m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more.) (B) Dicyclohexyl represented by the following general formula Pentadiene / phenolic polymer [Chemical formula 2] (However, in the formula, R ² represents _Cl H _{2l + 1} and l and n represent 0 or an integer of 1 or more, respectively.) (C) Methyl methacrylate / butadiene / styrene copolymer resin and (D) Average particle size Is an alumina powder of 10 to 50 μm as an essential component, and the alumina powder of (D) is contained in a proportion of 25 to 90% by weight based on the resin composition. 2. A semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with the cured product of the epoxy resin composition according to claim 1.